The Research Of Workpiece Positioning Algorithm For Virtual Maching Cell

Virtual machining is the essentially realization of physical machining, the establishment of it base on the model of mechanical technological systems. In virtual environment, it is necessarily to determine the positioning of workpiece model in the virtual machine tool, after the model is established. This thesis studies technology relating to model positioning against the requirement of processing simulation system, which has important theorical and values.First, the functional requirements of model positioning system are analysised, and the objectives of design for model positioning system are pointed out, The architecture of model positioning system is proposed, and the development platform for model positioning system is introduced.Second, this thesis studies model positioning technology in virtual environment. Intersection judgment algorithm of radial and triangle is deduced, using this algorithm can implement the function of picking up plane in virtual environment when a system is developed. The technology relating to trackball is studied, which implement the dynamic adjustment of eye coordinate system, it can make model translation, rotation, zoom in virtual environment. Through analyzes the type of geometric constraints between the plane, geometric constraint solving algorithm is studied, which can implement ubiety of the model.On the basis of above theoretic studies, model positioning system is developed. The component models in the system are created by the CAD software for 3D, through compile soft interface relatively to complete the model import function. In the system, it is allowable to make model translation, rotation, zoom. Through pick up base face and transform body, the system can implement ubiety of the body model, according to the type of geometric constraints which appointment.Finally, the system takes machine workpiece of a three-axis milling positioning clamping as an example, successfully completed the workpiece model positioning in system, validated the effectiveness of the algorithm.